Clockable secondary payload bridges for a payload adapter

ABSTRACT

A secondary payload bridge for a payload adapter is disclosed and includes a body portion, plurality of payload ports, and a secondary payload port. The plurality of attachment points are connected to the body portion of the secondary payload bridge. The plurality of attachment points are configured to removably attach the secondary payload bridge to the payload adapter to allow for clockable positioning of the secondary payload bridge around a circumference of the payload adapter. The secondary payload port is connected to the body portion. The secondary payload port is configured to releasably attach to a corresponding secondary payload.

INTRODUCTION

The present disclosure relates to payload adapters for spacecraft. Moreparticularly, the present disclosure relates to a clockable secondarypayload bridge that is removably attached to a payload adapter.

BACKGROUND

A launch vehicle carries one or more payloads from the surface of theEarth into space. For example, the launch vehicle may carry a primarypayload and several smaller secondary payloads. A payload adapter isused to independently support the primary payload and the secondarypayloads. One type of payload adapter forms an annular ring-shapedprofile, where secondary payload ports are disposed around acircumference of the payload adapter. After launch, the primary payloadis separated from the launch vehicle. In some instances, after theprimary payload separates the payload adapter then separates from thelaunch vehicle. The secondary payloads may be hosted on the payloadadapter for the duration of their mission life or, alternatively, thesecondary payloads may be deployed from the payload adapter into aspecific orbital state.

A payload adapter includes secondary payload ports that are each used tosecure a secondary payload. However, the location of the secondarypayload ports are static and may not be modified once the payloadadapter is fabricated. For example, one type of payload adapter includesa monocoque structure having an external skin, which is referred to as ashell. The secondary payload ports in the form of apertures that extendthrough the shell of the payload adapter. As a result, the specificlocation of the secondary payload ports of the payload adapter are fixedand may not change once they are formed within the shell of the payloadadapter. This also means that the location of the secondary ports of thepayload adapter are fixed and may not change once they are formed withinthe shell of the payload adapter. In order to fit within a pre-allocatedangular space within the launch vehicle's fairing, secondary payloadsfollow a standard or predefined volumetric constraint. However, thegeometry of the secondary payload often changes over time during thedesign process.

The launch vehicle should be balanced to ensure controllability duringlaunch. However, if the secondary payloads are not of equal mass or areattached to the payload adapter in a non-symmetrical manner, then thelaunch stack center of mass may exceed from the controllable offsetlimit. As a result, ballast may be required to provide balance. However,introducing ballast reduces the amount of useable payload mass that thelaunch vehicle may carry. Also, introducing ballast may also reduce thetargetable orbit energy, which is also referred to as delta-v, ifanother payload mass is held constant.

SUMMARY

According to several aspects, a secondary payload bridge for a payloadadapter is disclosed. The secondary payload bridge includes a bodyportion and a plurality of attachment points connected to the bodyportion of the secondary payload bridge. The plurality of attachmentpoints are configured to removably attach the secondary payload bridgeto the payload adapter to allow for clockable positioning of thesecondary payload bridge around a circumference of the payload adapter.The secondary payload bridge also includes a secondary payload port thatis connected to the body portion, where the secondary payload port isconfigured to releasably attach to a corresponding secondary payload.

In another aspect, a payload adapter is disclosed. The payload adapterincludes a main body having an annular profile defining a circumference,a forward open end, an aft open end, and a side structure connecting theforward open end and the aft open end to one another, and one or moresecondary payload bridges removably attached to the main body of thepayload adapter. Each secondary payload bridge includes a body portionand plurality of attachment points connected to the body portion of thesecondary payload bridge. The plurality of attachment points areconfigured to removably attach the secondary payload bridge to the mainbody of the payload adapter to allow for clockable positioning of thesecondary payload bridge around the circumference of the main body ofthe payload adapter. The secondary payload bridge also includes asecondary payload port that is connected to the body portion, where thesecondary payload port is configured to releasably attach to acorresponding secondary payload.

In still another aspect, a method for positioning a secondary payloadbridge around a circumference of a payload adapter is disclosed. Themethod includes removably attaching the secondary payload bridge to amain body of the payload adapter. The secondary payload bridge ispositioned at a first angular position around a circumference of thepayload adapter. The method also includes releasing the secondarypayload bridge from the main body of the payload adapter. The methodalso includes removably attaching the secondary payload bridge to themain body of the payload adapter at a second angular position around thecircumference of the payload adapter, where the first angular positionrepresents a different angular position about a rotational axis of thepayload adapter than the second angular position.

The features, functions, and advantages that have been discussed may beachieved independently in various embodiments or may be combined inother embodiments further details of which can be seen with reference tothe following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a cross-sectioned view of a forward end of a launch vehicleincluding a fairing, a primary payload, a payload adapter, and aplurality of secondary payloads, according to an exemplary embodiment;

FIG. 2 is a perspective view of the payload adapter having a pluralityof secondary payloads mounted thereon, according to an exemplaryembodiment;

FIG. 3 is a perspective view of an alternative embodiment of the payloadadapter, where the secondary payloads are located within the payloadadapter's circumference, according to an exemplary embodiment;

FIG. 4 is a perspective view of the payload adapter and the secondarypayload bridges, according to an exemplary embodiment;

FIG. 5 illustrates one of the secondary payload bridges shown in FIG. 4, according to an exemplary embodiment;

FIG. 6A is a schematic diagram of the payload adapter and four secondarypayload bridges arranged equidistant from one another, according to anexemplary embodiment;

FIG. 6B is an illustration of the payload adapter shown in FIG. 6A,where one of the secondary payload bridges have been moved in acounterclockwise direction, according to an exemplary embodiment;

FIG. 7 is an alternative embodiment of the payload adapter and thesecondary payload bridges, according to an exemplary embodiment;

FIG. 8 is an alternative embodiment of the payload adapter having aforward ring that has a smaller diameter than an aft ring, according toan exemplary embodiment;

FIG. 9 illustrates the payload fairing where a plurality of the payloadadapters are stack on top of one another, according to an exemplaryembodiment;

FIG. 10 is an illustration of the payload adapter having a monocoquestructure, according to an exemplary embodiment;

FIG. 11 is an illustration of the payload adapter having a monocoquestructure, where a plurality of stringers are disposed along anoutermost surface of the shell, according to an exemplary embodiment;and

FIG. 12 is a process flow diagram illustrating an exemplary method forpositioning the secondary payload bridge 40 around the circumference 54(FIG. 4 ) of the payload adapter.

DETAILED DESCRIPTION

The present disclosure is directed towards a clockable secondary payloadbridge for a payload adapter. The secondary payload bridge includes asecondary payload port. The secondary payload port is configured toreleasably attach to a corresponding secondary payload. The secondarypayload bridge further includes plurality of attachment points that areconfigured to removably attach the secondary payload bridge to thepayload adapter. The attachment points allow for dynamic positioning ofthe secondary payload bridge around a circumference of the payloadadapter. It follows that the secondary payloads are also clockablearound the circumference of the payload adapter. The clockable secondarypayload bridges allow for the position of the secondary payloads to beadjusted on an ongoing basis.

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

Referring to FIG. 1 , a portion of an exemplary launch vehicle 10 isshown. The launch vehicle 10 includes a payload fairing 20, a primarypayload 22, a payload adapter 24, a plurality of secondary payloads 26,and a launch adapter 30. The primary payload 22, the payload adapter 24,the plurality of secondary payloads 26, and the launch adapter 30 arehoused within the payload fairing 20. The launch vehicle 10 carries theprimary payload 22 and the plurality of secondary payloads 26 from theEarth's surface and into space. In one example, the primary payload 22is a satellite that is configured to orbit Earth. The primary payload 22is supported by the payload adapter 24. The secondary payloads 26 aremounted to the payload adapter 24 in a location below the primarypayload 22. The payload adapter 24 is seated upon the launch adapter 30.

FIG. 2 is a perspective view of the payload adapter 24, the plurality ofsecondary payloads 26, and a solar panel array 28 disposed at a forwardopen end 42 of the payload adapter 24. In the non-limiting embodiment asshown, six secondary payloads 26 of unequal size and mass are radiallymounted to the payload adapter 24, however, it is to be appreciated thatFIG. 2 is merely exemplary in nature and that any number and compositionof secondary payloads 26 may be mounted to the payload adapter 24.Although FIG. 2 illustrates the secondary payloads 26 spacedequidistantly apart, the location of the secondary payloads 26 may beadjusted as explained below. Referring to both FIGS. 1 and 2 , in anembodiment the secondary payloads 26 are each arranged radially aroundan outermost side 36 of the payload adapter 24. However, in thealternative embodiment as shown in FIG. 3 , the secondary payloads 26are arranged around an innermost side 38 of the payload adapter 24.

Each secondary payload 26 is mounted to the payload adapter 24 by acorresponding secondary payload bridge 40, which is shown in FIG. 4 .Referring now to FIG. 4 , the secondary payload bridges 40 are removablyattached to a main body 34 of the payload adapter 24. In the embodimentas shown in the figures, the payload adapter 24 is a ring adapter.Accordingly, the payload adapter 24 has an annular profile defining acircumference 54. The secondary payload bridges 40 are disposed aroundeither or both the outermost side 36 (FIG. 2 ) or the innermost side 38(FIG. 3 ) of the payload adapter 24.

The payload adapter 24 includes a forward open end 42 defined by aforward ring 44, an aft open end 46 defined by an aft ring 48, and aside structure 52 connecting the forward ring 44 to the aft ring 48. Inthe embodiment as shown in FIG. 4 the side structure 52 is a pluralityof truss supports 50 connecting the forward ring 44 and the aft ring 48to one another. In an embodiment, the truss supports 50 are constructedof a carbon fiber reinforced polymer composite material. However, inanother embodiment, the truss supports 50 are constructed of astructural material such as, for example, aluminum. The forward ring 44is configured to either directly or indirectly couple to the payloadadapter 24 to the primary payload 22 (FIG. 1 ), and the aft ring 48 isconfigured to either directly or indirectly couple the payload adapter24 to the launch adapter 30 (FIG. 1 ). In an embodiment, the forwardring 44 and the aft ring 48 are constructed of a structural materialsuch as, for example, stainless steel or aluminum.

In the embodiment as shown in FIG. 4 , the payload adapter 24 is a trussstyle payload adapter. That is, the plurality of truss supports 50 areconfigured to bear the loads exerted upon the payload adapter 24. In theembodiment as shown in the figures, the plurality of truss supports 50are oriented at consistent angles to form alternately inverted isoscelestriangle-shaped openings 59 around the circumference 54 of the payloadadapter 24. This orientation may be referred to as a Warren trussarrangement. However, it is to be appreciated that other trussarrangements may be used as well. It is also to be appreciated that theside structure 52 is not limited to the truss supports 50. For example,in the embodiment as shown in FIG. 10 , the secondary payload bridges 40are removably attached to a monocoque structure, and the side structure52 is a shell 86.

Referring back to FIG. 4 , a plurality of mounting fixtures 56 aredisposed around the circumference 54 payload adapter 24. The mountingfixtures 56 are each configured to releasably attach to the plurality ofattachment points 62 of one of the secondary payload bridges 40. Forexample, in the embodiment as shown in FIG. 4 , the mounting fixtures 56are a plurality of bolt holes 58 that are disposed around the forwardring 44 and a plurality of bolt holes 60 disposed around the aft ring48. Although FIG. 4 illustrates the mounting fixtures 56 disposed aroundthe outermost side 36 of the payload adapter 24, in an alternativeembodiment the mounting fixtures 56 are disposed around the innermostside 38 (FIG. 3 ) of the payload adapter 24.

Similarly, each secondary payload bridge 40 is removably attached to thepayload adapter 24 by a plurality of attachment points 62. For example,in the embodiment as shown in FIG. 5 , the plurality of attachmentpoints 62 include one or more bolt holes 64 located on an upper arm 68and one or more bolt holes 66 located on each lower arm 70 of thesecondary payload bridge 40. The secondary payload bridges 40 aredisposed along either the outermost side 36 (FIG. 2 ) or the innermostside 38 (FIG. 3 ) of the payload adapter 24. Although removableattachment is described, it is to be appreciated that in one embodimentafter attachment the secondary payload bridge 40 may then be permanentlyattach to the payload adapter 24.

Referring back to FIG. 4 , a plurality of corresponding fasteners 72 areused to secure the secondary payload bridge 40 to the payload adapter24. Therefore, the secondary payload bridge 40 is released from thepayload adapter 24 by removing the corresponding fasteners 72 from therespective bolt holes 58, 64, and 66. Although FIG. 4 illustratesfasteners 72 such as bolts, it is to be appreciated that FIG. 4 ismerely exemplary in nature, and any other device for releasablyattaching the secondary payload bridges 40 to the payload adapter 24 maybe used as well. For example, in another embodiment, the secondarypayload bridges 40 are secured to the payload adapter 24 by clamping,drilling on assembly, or by slots.

FIG. 5 is perspective view of one of the secondary payload bridges 40shown in FIG. 5 . The secondary payload bridge 40 includes a bodyportion 74, where the plurality of attachment points 62 are connected tothe body portion 74. The secondary payload bridge 40 also includes asecondary payload port 78 that is connected to the body portion 74,where the secondary payload port 78 is configured to releasably attachto a corresponding secondary payload 26 (FIGS. 1 and 2 ). In thenon-limiting embodiment as shown, the secondary payload port 78 includesa round profile 51, where the secondary payload 26 is mounted radiallyto the secondary payload port 78, however it is to be appreciated thatother types of profiles may be used as well.

The secondary payload bridges 40 may be removed from the payload adapter24 and then reattached in a different location of the payload adapter 24by the fasteners 72. For example, FIG. 6A is a schematic diagramillustrating four secondary payload bridges 40A, 40B, 40C, 40D spacedequally, and the secondary payload bridge 40A is in a first angularposition 1A. Turning now to FIG. 6B, the top secondary payload bridge40A has been moved counterclockwise to the left, and into a secondangular position 1B. Accordingly, it is to be appreciated that thesecondary payload bridges 40 are clockable about a rotational axis A-Aof the payload adapter 24. In other words, an angular position of eachsecondary payload bridge 40 about the rotational axis A-A of the payloadadapter 24 is adjustable. Therefore, each secondary payload bridge 40may be located in various respective angular positions about therotational axis A-A of the payload adapter 24. It follows that theposition of each secondary payload 26 (FIGS. 1 and 2 ) may also beshifted in various respective angular positions about the rotationalaxis A-A of the payload adapter 24. Thus, the plurality of attachmentpoints 62 (FIG. 4 ) of the secondary payload bridges 40 and theplurality of mounting fixtures 56 disposed around the circumference 54(FIG. 4 ) of the payload adapter 24 allow for clockable or selectiveangular rotational positioning of a corresponding secondary payloadbridge 40 about to the longitudinal axis A-A of the payload adapter 24.

Referring to FIGS. 4 and 5 , in an embodiment the body portion 74 of thesecondary payload bridge 40 is constructed of a structural material suchas aluminum. In an exemplary embodiment, the body portion 74 of thesecondary payload bridge 40 is constructed of at least one of thefollowing materials: aluminum, titanium, steel, and a compositematerial. In the embodiment as shown in FIG. 4 , the body portion 74 ofthe secondary payload bridge 40 is composed of a plurality of trusses76. For example, FIG. 4 illustrates the plurality of trusses 76 arrangedin a four-point bridge to support the secondary payload port 78. Thatis, the trusses 76 are arranged so as to define four corners or points79A, 79B, 79C, 79D arranged in a square or rectangular pattern Avertically oriented truss 76 connects points 79A and 79D to one anotherand another vertically oriented truss 76 connects points 79B to 79C toone another.

Although FIG. 4 illustrates the mounting fixtures 56 disposed around theforward ring 44 and the aft ring 48, it is to be appreciated that thisembodiment is merely exemplary in nature, and the mounting fixtures 56are not limited to the forward and aft rings 44, 48. For example, in theembodiment as shown in FIG. 7 , the payload adapter 24 includes an upperring 100 and a lower ring 102 that are both disposed between the forwardring 44 and the aft ring 48. Specifically, the upper ring 100 isdisposed between the forward ring 44 and the lower ring 102, and thelower ring 102 is disposed between the upper ring 100 and the aft ring48. The upper ring 100 and the lower ring 102 are both attached to thetruss supports 50 of the payload adapter 24. The upper ring 100 and thelower ring 102 both include the plurality of mounting fixtures 56 (notvisible in FIG. 7 ), which are configured to releasably attach to one ofthe plurality of attachment points 62 of the secondary payload bridge 40(also not visible in FIG. 7 ). Similar to the embodiment as shown inFIG. 4 , the mounting fixtures 56 any device for releasably attachingthe secondary payload bridges 40 to the payload adapter 24 such as, forexample, bolts.

FIG. 7 also illustrates the secondary payload bridges 40 constructed ofa wall structure 110 instead of the plurality of trusses 76 shown inFIG. 4 . In the exemplary embodiment as shown, the secondary payloadport 78 is an aperture 106 that extends through the wall structure 110of the corresponding secondary payload bridge 40.

FIGS. 4 and 7 illustrate the forward ring 44 and the aft ring 48 havingidentical diameters D. That is, the forward ring 44 and the aft ring 48are identical in size. However, in the alternative embodiment as shownin FIG. 8 , the forward ring 44 and the aft ring 48 both have unequaldiameters. Specifically, in the non-limiting embodiment as shown in FIG.8 , the forward ring 44 includes a forward diameter D1 and the aft ring48 includes an aft diameter D2, where the forward diameter D1 is lessthan the aft diameter D2. However, it is to be appreciated that inanother embodiment the forward diameter D1 is greater than the aftdiameter D2. The forward diameter D1 of the forward ring 44 and the aftdiameter D2 of the aft ring 48 are determined based on the specificpackaging requirements of the launch vehicle 10 (FIG. 1 ).

FIG. 9 is an exemplary embodiment of the payload fairing 20 and aplurality of payload adapters 24 that are located within the payloadfairing 20. In the example as shown, four separate payload adapters 24are stacked on top of one another. It is to be appreciated that theplurality of truss supports 50 (shown in FIG. 4 ) of the payload adapter24 result in reduced mass and increased strength when compared to someother types of conventional payload adapters presently available. Forexample, it may only be possible to stack two or three conventionalpayload adapters on top of one another because of their limited strengthand heavy mass. In contrast, it may be possible to stack up to five orsix of the payload adapters 24 on top of one another due to theincreased strength and reduced mass provided by the truss supports 50.In an embodiment, the number of payload adapter 24 stacked on top of oneanother may be limited by the available volume within an interior 98 ofthe payload fairing 20, and not by the strength of the payload adapters24 themselves.

In an alternative embodiment as shown in FIG. 10 , the main body 34 ofthe payload adapter 24 includes a monocoque structure defining the shell86. The shell 86 carries the stress of the loads exerted upon thepayload adapter 24. The shell 86 of the payload adapter 24 connects theforward ring 44 to the aft ring 48. The shell 86 defines a continuousinnermost surface 88 and a continuous outermost surface 90. In thenon-limiting embodiment as shown in FIG. 10 , the mounting fixtures 56are disposed around the forward ring 44 and the aft ring 48 of thepayload adapter 24. However, in the embodiment as shown in FIG. 11 , themounting fixtures 56 are disposed on the shell 86 of the monocoquestructure of the payload adapter 24.

Referring now to FIG. 11 , in another embodiment the outermost surface90 of the shell 86 of the payload adapter 24 defines a plurality ofstringers 104. In the exemplary embodiment as shown in FIG. 11 , theplurality of stringers 104 extend vertically along the outermost surface90 of the shell 86 between the forward ring 44 and the aft ring 48 ofthe payload adapter 24. In other words, the plurality of stringers 104are parallel with the axis of rotation A-A of the payload adapter 24.However, in another embodiment, the plurality of stringers 104 aredisposed circumferentially around the shell 86 and are perpendicularwith respect to the axis of rotation A-A of the payload adapter 24.Although FIG. 11 illustrates the plurality of stringers 104 disposedalong the outermost surface 90 of the shell 86, it is to be appreciatedthat the plurality of stringers 104 may be disposed along the innermostsurface 88 of the shell 86 as well.

The stringers 104 are each shaped to receive fasteners 72 (FIG. 4 ),such as the shank portion of a bolt. The wall structure 110 of eachsecondary payload bridge 40 defines the plurality of attachment points62. In the embodiment as shown, the plurality of attachment points 62are apertures 112 that extend through the wall structure 110 of thecorresponding secondary payload bridge 40. FIG. 11 depicts eachsecondary payload bridge 40 having the attachment points 62 disposedaround an outer periphery 114 of the wall structure 110. Moreover, theouter periphery 114 of the secondary payload bridges 40 include a squareprofile 120, and an attachment point 62 is disposed at each corner 122of the square profile 120. However, it is to be appreciated that FIG. 11is merely exemplary in nature, and the secondary payload bridges 40 mayinclude other profiles as well.

FIG. 12 is an exemplary process flow diagram illustrating a method 200for positioning the secondary payload bridge 40 around the circumference54 (FIG. 4 ) of the payload adapter 24. It is to be appreciated that inone embodiment, once a position of the secondary payload bridge 40 isfinalized, the secondary payload bridge 40 is then permanently attachedto the secondary payload bridge 40. Referring to FIGS. 1, 6A, 6B, and 12, the method 200 begins at block 202. In block 202, the secondarypayload bridge 40A is removably attached to the main body 34 of thepayload adapter 24 at the first angular position 1A, which is shown inFIG. 6A. As mentioned above, the secondary payload bridge 40 isremovably attached to the payload adapter 24 to allow for clockablepositioning around the circumference 54 of the payload adapter 24.

As seen in block 202A, the secondary payload bridge 40 is removablyattached to the payload adapter 24 by the plurality of attachment points62 connected to the body portion 74 of the secondary payload bridge 40.The method 200 may then proceed to block 204.

In block 204, the secondary payload bridge 40 is released from thepayload adapter 24. For example, as seen in block 204A, in oneembodiment the secondary payload bridge 40 is released from the payloadadapter 24 by removing the corresponding fasteners 72 that secure thesecondary payload bridge 40 to the payload adapter 24. The method 200may then proceed to block 206.

In block 206, the secondary payload bridge 40 is removably attached tothe main body 34 of the payload adapter 24 at a second angular positionA2 (seen in FIG. 6B) around the circumference 54 of the payload adapter24. Referring to both FIGS. 6A and 6B, the first angular position A1represents a different angular position about the rotational axis A-A ofthe payload adapter 24 than the second angular position A2. The method200 may then terminate.

Referring generally to the figures, the disclosed secondary payloadbridges provide various technical effects and benefits. Specifically, apayload bridge includes a plurality of attachment points that areconfigured to removably attach the secondary payload bridge to a payloadadapter. The attachment points allow for clockable positioning of thesecondary payload bridge around a circumference of the payload adapter.It follows that the secondary payloads are also clockable around thecircumference of the payload adapter. The clockable secondary payloadbridges allow for the position of the secondary payloads to be adjustedon an ongoing basis. The disclosed secondary payload bridges alsosupport non-standard secondary payload geometries to be secured to thepayload adapter. Furthermore, the shape or mass of the secondarypayloads may be changed during development of the payload without theneed to re-design the payload adapter.

The description of the present disclosure is merely exemplary in natureand variations that do not depart from the gist of the presentdisclosure are intended to be within the scope of the presentdisclosure. Such variations are not to be regarded as a departure fromthe spirit and scope of the present disclosure.

What is claimed is:
 1. A secondary payload bridge for a payload adapter,the secondary payload bridge comprising: a body portion composed of aplurality of trusses; plurality of attachment points connected to thebody portion of the secondary payload bridge, wherein the plurality ofattachment points are configured to removably attach the secondarypayload bridge to the payload adapter to allow for clockable positioningof the secondary payload bridge around a circumference of the payloadadapter; and a secondary payload port that is connected to the bodyportion, wherein the secondary payload port is configured to releasablyattach to a corresponding secondary payload.
 2. The secondary payloadbridge of claim 1, wherein the plurality of trusses are arranged in afour-point bridge.
 3. The secondary payload bridge of claim 1, whereinthe body portion of the secondary payload bridge defines a wallstructure, and wherein the secondary payload port is an aperture thatextends through the wall structure.
 4. The secondary payload bridge ofclaim 1, wherein the body portion of the secondary payload bridge isconstructed of at least one of the following: aluminum, titanium, steel,and composite material.
 5. A payload adapter, comprising: a main bodyhaving an annular profile defining a circumference, a forward open end,an aft open end, and a side structure connecting the forward open endand the aft open end to one another; and one or more secondary payloadbridges removably attached to the main body of the payload adapter,wherein each secondary payload bridge comprises: a body portion composedof a plurality of trusses; plurality of attachment points connected tothe body portion of the secondary payload bridge, wherein the pluralityof attachment points are configured to removably attach the secondarypayload bridge to the main body of the payload adapter to allow forclockable positioning of the secondary payload bridge around thecircumference of the main body of the payload adapter; and a secondarypayload port that is connected to the body portion, wherein thesecondary payload port is configured to releasably attach to acorresponding secondary payload.
 6. The payload adapter of claim 5,wherein the main body of the payload adapter includes a monocoquestructure defining a shell.
 7. The payload adapter of claim 6, whereinthe plurality of attachment points of the secondary payload bridgereleasably attach to the shell of the payload adapter.
 8. The payloadadapter of claim 5, wherein the forward open end of the main body of thepayload adapter is defined by a forward ring and the aft open end of themain body of the payload adapter is defined by an aft ring.
 9. Thepayload adapter of claim 8, wherein the both the forward ring and theaft ring include a plurality of mounting fixtures that are configured toreleasably attach to one of the plurality of attachment points of thesecondary payload bridge.
 10. The payload adapter of claim 8, whereinthe payload adapter further comprises an upper ring and a lower ringthat are disposed between the forward ring and the aft ring.
 11. Thepayload adapter of claim 10, and wherein the upper ring and the lowerring both include a plurality of mounting fixtures configured toreleasably attach to one of the plurality of attachment points of thesecondary payload bridge.
 12. The payload adapter of claim 5, whereinthe plurality of trusses are arranged in a four-point bridge.
 13. Thepayload adapter of claim 5, wherein the body portion of the secondarypayload bridge defines a wall structure, and wherein the secondarypayload port is an aperture that extends through the wall structure. 14.The payload adapter of claim 5, wherein the body portion is constructedof at least one of the following: aluminum, titanium, steel, and acomposite material.
 15. A method for positioning a secondary payloadbridge around a circumference of a payload adapter, the methodcomprising: removably attaching the secondary payload bridge to a mainbody of the payload adapter, wherein the secondary payload bridge ispositioned at a first angular position around a circumference of thepayload adapter and includes a body portion composed of a plurality oftrusses; releasing the secondary payload bridge from the main body ofthe payload adapter; and removably attaching the secondary payloadbridge to the main body of the payload adapter at a second angularposition around the circumference of the payload adapter, wherein thefirst angular position represents a different angular position about arotational axis of the payload adapter than the second angular position.16. The method of claim 15, further comprising: removably attaching thesecondary payload bridge to the payload adapter by a plurality ofattachment points connected to the body portion of the secondary payloadbridge.
 17. The method of claim 15, further comprising: releasing thesecondary payload bridge from the payload adapter by removingcorresponding fasteners that secure the secondary payload bridge to thepayload adapter.
 18. The method of claim 15, wherein the secondarypayload bridge secondary includes a secondary payload port configured toreleasably attach to a corresponding secondary payload.
 19. Thesecondary payload bridge of claim 1, wherein the plurality of trussesdefines four corners arranged in either a square pattern or arectangular pattern.
 20. The payload adapter of claim 5, wherein theplurality of trusses defines four corners arranged in either a squarepattern or a rectangular pattern.